Confounder selection evidence matrix ==================================== StatMedAnalysis | Original downloadable worksheet | 6 November 2026 Choose adjustment variables using causal roles and measurement timing. How to use this worksheet List plausible common causes of exposure and outcome before looking at association p-values. Record the substantive evidence and whether measurement precedes exposure. Draw the proposed relationships and identify competing causal explanations. Keep adjustment decisions independent of whether they improve statistical significance. Save a working copy and keep the original blank version. Use public, hypothetical or aggregate information only; do not enter patient identifiers, credentials or confidential records. Keep source evidence in your approved project workspace. Mark unresolved text fields UNKNOWN or NOT REPORTED with a reason; never substitute zero for an unknown count. Project/version __________________ Prepared by role/date __________________ Working fields 1. Candidate variable Response/evidence: _________________________________________________________ ___________________________________________________________________________ 2. Role in proposed causal structure Response/evidence: _________________________________________________________ ___________________________________________________________________________ 3. Timing relative to exposure Response/evidence: _________________________________________________________ ___________________________________________________________________________ 4. Supporting subject-matter evidence Response/evidence: _________________________________________________________ ___________________________________________________________________________ 5. Measurement quality or proxy limitation Response/evidence: _________________________________________________________ ___________________________________________________________________________ 6. Included adjustment set Response/evidence: _________________________________________________________ ___________________________________________________________________________ 7. Alternative structure and sensitivity Response/evidence: _________________________________________________________ ___________________________________________________________________________ 8. Unmeasured common causes Response/evidence: _________________________________________________________ ___________________________________________________________________________ Hypothetical worked case A fictional baseline severity score affects treatment choice and later recovery. A severity score recorded after treatment may partly reflect treatment response and cannot automatically replace the baseline measure. Decision rule and limitations Retain variables because their causal role supports the chosen estimand. Investigate mediators and colliders separately; p-value screening does not identify a sufficient adjustment set. Decision _______________________ Remaining uncertainty ____________________ Next action ____________________ Owner / review date ______________________ Independent check and discrepancy resolution _______________________________ Official method or reporting reference checked 6 November 2026 https://miguelhernan.org/whatifbook This is an original planning aid, not an official checklist, validated instrument, clinical recommendation or certificate of expert approval. Apply the referenced guidance to the specific design and record any additional requirements.